Method of and apparatus for cooling and ventilating



May 4 1926.

L. L. Lgwls METHOD OF AND APPARATUS FOR COOLING AND VENTILATING.

Filed Dec. 22 1924 r V //v' f/vrk (awn ATTQRNEVi- Patented May 1926.

i U-NlT ED sTATEs PATENT orP icE.

' LEO L. LEWIS, OF PIJAIN FIELD, NEW JERSEY, ASSIGNOR TO CARRIER ENGINEERING CORPORATION, OF NEWARK, NEW JERSEY.

-MET-HOD or AND APPARATUS, FOR COOLING AND VENTILAT'ING.

Application filed December 22, 192i. Serial No. 757,389. 7

To all whom it may concern:

Be it known that I, LEO L. LEWIS, a citizen of the United States, residing at Plainfield, in the county of Union and. State of New Jersey, have invented a new and. useful Improvement in Methods of and Ap aratus for Cooling and Ventilating, of which the following is a specification.

Thisjnvention relates tothe cooling and 10 ventilating of rooms orbuildings and has reference more particularly to a method of and apparatus'for cooling and ventilating which is especially adapted to be used in rooms or buildings where peoplecongregate,

such as theaters, a uditoriums, assembly rooms, schools, and other enclosures occupied by people inconsiderable numbers.

For the greatest comfort of people as-.

' sembled' in such places, it is desirable to maintain a comparatively low relative humidity j of the air, preferably not greater than about 50 percent, since a high relative hu- 'midity causes greater discomfort than a I lower relative humidity with a higher temperature. It is also desirable, especially in the summer months to maintain the room temperature and humidlty as low as'prac- .ticable and to keep the air clrc-ulatmg so as to quickly, absorb the heat and moisture from the bodies and exhalations of the people in the room. It is also-important that the v air admitted through the supply ducts or the like near persons in the room should not have a temperature more than about 8 degrees lower than the average room temperature or said-air current will cause discomfort to the individuals.

In ventilating and cooling systems for similar purposes as heretofore designed, the

40 greater part of the air which is recirculated is passed through a dehumidifier where its temperature is reduced as much as 25 degrees to 30 degrees below the dry bulb temperature in the room in order to reduce the relative ture was too cold to reintroduce into the reheated at additional erzpense so that the system is expensive to operate as to costof humidity of the air which has been unduly room containing the people without dis-. comfort to the latter, said air had to be refrigeration and heating. This method moreover, requires the operation of a boiler during the summer season, which is ob jectionable. i y v An object of this invention is to produce a practical and efficient cooling and ventilatng system for theaters and other enclosures in which people congregate in considerable numbers, in which a desirable temperature and relative humidity are maintained in the enclosure regardless of the number of people therein, and in which the air for ventilating and coohng is supplied to the enclosure with the greatest comfort to the people therein. a I

Other objects of the invention are to produce an efficient cooling and ventilating system which is economical in operation, and can. be installed with a minimum initial investment; also to provide a cooling and ventilating system in which the bulk of the air is recirculated without being conditioned, and only. a small part of the.air supplied to the enclosure is. taken from the outside.

and'conditioned or dehumidifiedand then mixed with the recirculated air, thus saving in refrigeration, and eliminating the necessity of means for reheating the air during the summer months; also to provide a sysl tem of the class described, in which the conditioned or dehumidified air is perfectly I blended or mixed with the recirculatedvair to produce a mixture having a sufficiently high temperature so as not to produce discomfort to the'occupants when the mixed air is introduced into the enclosure; also i to cause the requisite amountof vitiated air containing moisture eva orated and respired from the persons to be c ischarged out of the enclosure instead of being pussedthrough the dehumidifier, thus saving in refrigeration; also to provide a system of the classdescribed in which the admission of fresh air from the outside and the relief'of vitiated airv from the enclosure are automatically regulated so as to maintain the desired con- (llllODS of temperature and relative humidity in the enclosure, and also to impri' ve cooling and ventilating methods and apparatus in other respects hereinafter claimed." I V q .In the accompanying drawings:

Fig. 1 is a diagrammatic sectional elevaspecified and he reversed and the air introduced at the tion of a building equipped with apparatus embodying my invention forcarrying out my improved cooling and ventilating method.

Fig. 2 is a diagrammatic view of the damper-.mechaiiism thereof.

-' The drawings illustrate an arrangement of apparatus suitable for a theater building 10, of ordinary construction, havin a stage 11, ah balcony 12, and a main au itorium; 13, The balcony 12 and auditorium 13 are rovided, as usual, "with-seats 14 under w ich are shown ventilators of the mushroom type r 15 connected by openings through the floor to a ventilating chamber or passage 16 under the balcony 12 and to a corresponding ventilating passage or chamber 20 under the auditorium. I

In the preferred arrangement illustrated, the air conditioning or cooling apparatus is located in a chamber or s ace 21 above the balcony, and the air is mtroduced at the u per portions of the occupied spaces and withdrawn at the floors. It should be understood, however, that the arrangement may lower portions of the occupied spaces and exhausted at the upper portions thereof.

With the arrangement shown, however, considerabl less air is necessary for the proper 3 ventilation of the enclosure. In some cases the decorations in thexbuilding or other structural features would. prevent the location of the apparatus as shown.

According to may improved ventilatin and cooling method, the greater portion 0 the air, preferably not less than about 7 5 percent of the air withdrawn from the enclosure: is recirculated and returned to the enclosure, the remaining smaller portion being allowed to escape into the atmosphere. The air thus exhausted into the atmosphere 'is replaced by taking a corresponding volume of fresh air' fro'mfthe outside and dehumidifying or conditioning this fresh air to the required dew point, sozthat by then mixing this conditioned air with the warmer recirculated air, a resultant ainmix'ture having a temperature. of about 72 degrees F. and a sufficiently low relative humidity is obtained, and this mixed 'air is admitted into the enclosure.

The heat giveniolf by each person in the '5 room amounts to approximately 4 B. t. u.'

per minute andthere will be respired from and evaporated from the body of each person about 0.1 pound of water per hour. The

volume of air supplied to the 'eDOI therefore, is such that by properly regulating the proportions of conditioned and recirculated air,-the temperature in the enclo- I -sure will not increase above F. and the relative humidity will not exceed about 50 percent notwithstanding the heat and moisture given off by the people in the room It should be noted that the maximum diifer- "more oppressive than a high temperature.

The-proportions of fresh air and recirculated air can be varied over fairly wide limits and in' fact the apparatus to be described is adapted to automatically vary these proportions to suit the changing conditions from an empty room to a room which is full of people. v

For the purpose of securing the requlred low dew point .of the fresh air admitted, an air conditioning device or dehumidifier 22 is conditioned by contact with water sprays of known type is employed, in which the air 23. In warm weather, when it is necessary to-cool and dehumidify the air, the spray" water is cooled by suitable refrigeration apparatus, not shown. The air conditioner 22 is equipped with a dew point control indicated at 23 of any known or suitable type adapted ,to regulate the temperature in the conditioner so that the air leaving the same will have the required predetermined dew point. For example, during the summer months when dehumidification is required,

this control is adapted to regulate thevolume of refrigerated water admitted to the sprays, while during the winter months the control is adapted'to regulate the supply of steam for heatin the spray water. Dew point controls 0 this nature are well known. From the dehumidifier 22, the air passes through a: mixing chamber 24 connected to i the suction side of a main blower or .fan

25. The dehumidifier 22 is connected by a duct 26 to a fresh air admission tower '27 preferably located on the roof of the building, and a heater or tempering coil 28 is preferably located between the duct 27 and dehumidifier 22, said heater being supplied by steam through .a pipe 29 so as to temper the air from the outside before it enters the dehumidifier. This tempering coil is simply to relieve the Work of the usual automatic dew point control 'of the dehumidifier 22, and is only necessary in cold weather. The steam admitted through the'pipe 29 can be cont-rolled either by .hand or automatically by a thermostat-located in the fresh air duct 26, as desired. I 4

r The cool fresh air passin through the dehumidifier 22 passes'into t e mixing chamber 2 1 where it is preferably mixed with a much larger volume of the air-withdrawn from the room and returned through a duct 30. The. duct 30 connects at one end with the discharge of a blower 31,'whic'\ is con-l3 nected to asuction duct 32. 'The duct 32, as

shown, has a branch 33 leading from the ex-- haust chamber 16 of the balcony 12 and a branch 34 leading from the exhaust chamber 20 of the auditorium 13.

The other end of the return duct has a branch leading to a relief tower 36, preferably located on the-roof of the building, and a second branch 37 connecting with the mixing chamber 24 so thatthe recirculated air or the required portion thereof can be thoroughly mixed withthe fresh air passing into the mixing chamber 24 through the dehumidifier 22. The mixing of the two grades of air, is made more complete by passing the mixture through the blower 25, the churning action of which accomplishes aperfect mixture. The discharge duct 38. of the blower 25, is provided with 'a branch pipe 39 which delivers its air into the upper portion of the space above, the balcony 12, and a second branch 40 connected-t0 a register or outlet 41loc'ated so as to deliver air into the upper part of the auditorium.

In the summer months it will ordinarily not be necessary to-heat the air after passing through the blower 25 owing to the fact that the mixture of the small. percentage of cold fresh air with the larger percentage of recirculated air produces a resultant temperature of the mixed air which is suitable for admission into the room. However, in the winter months it may be necessary to heat the air delivered to the room,

and for this purpose a heater 42 is provided in the supply duct 39, and a heater 48 in the duct 40, said heaters being supplied by steam through pipes 44 and 45 re spectively. A thermostat 46 is provided. in l the exhaust duct 34 and a thermostat- 47 is located inthe exhaust duct 33 from the balcony 12. A diaphragm valve 48 is provided on the steam pipe 44 and a diaphragm valve 49 on the steam pipe 45, said di a-. 'phragm-valves being connected by a r lines.

or otherwise to the thermostats 47- and 46 respectively so that the temperature of air exhausted from the balcony and auditorium regulates automatically and independently the temperature of air introduced to said balcony and auditorium. Any other suitable thermostatic regulating means for simi-'" ployed.

For controlling the relative humidity in larlv controlling the heaters could be emthe room, a suitable hygrostat or device 50 responsive to changes in humidity is positioned preferably in the return duct 30, so as'to be influenced by the air exhausted from" the room. This hygrostat 50is operatively connected as by an air pressure line 51, with'a motor 52 which is connected by actuating mechanism to dampers 53, 54 and 55 controlling respectively the fresh air admission duct 26, the relief air duct 'ity of the air, and the increase in tends to offset that reduction,

'versa. Thus the motor 52 operates to admit an amount of freshair to the dehumidifier equal to the amount of air discharged into-the atmosphere through the relief duct 35, and when the fresh air-inlet damper is closed the relief damper will also be closed and all of the air (except if desired, a predetermined small minimum) will be recirculated and returned to the room without be I ing conditioned. 55 In-the operation of the system, thetwo thermostats 46 and 47 are set at the minimum temperature, which preferably would beabout 68, andthis minimum temperature would be maintained so long as the house or enclosure remains empty, or when it contains only a very few people. The hygrostat '50 is adjusted to control at the desired relative humidity which ordinarily will be 45 percent to 50 percent, say 50 percent. When the enclosure is empty, the dew point of the air in it will be determined by the point at which the dew int .control of the dehumidifier 22 is set. El the hygrostat 50 is set for 50 percent relative humidity, and ion the" thermostats 46. and 47 set for'a minimum temperature of 68 F., then the dew point control of the dehumidifier would be set for 49 F. which is the dew point required for the fresh air leaving the de- 5'" humidifier 24 to produce'50 percent relative humidity at-68 in the enclosure. \Vith-no people in the house, all of these controls would be in equilibrium and dampers 53,

54. would be closed or nearly closed, so that 1 and second, to increase the dew point due to the moisture evaporated from their bodies and carried by respired air. Both of these conditions affect the air passing over the hygrostat 50. The rise in dry bulb temperature tends to reduce the relative humiddew point but the effect of the change in the dry! bulb temperature is much greater than the other. hen the hygrostat 50 is so affected, itis thrown out of equilibrium and opens the dampers '53 1.30 i

and 54; the necessary amount and correspondingly closes the dampers 55 so that a greater volume of fresh air is admitted through the dehumidifier 22. This gives a E greater cooling capacity to absorb the additional heat and offsets the moisture given off by the .people. As the number of people increases, the dampers 53 and 54 will be,

gradually opened more and more until the reached The hygrosta-t 50 functions in the same manner, regardless of whether steam has been turned on in heaters 42 and43, or not.v These heaters, which are controlled bytherinostats 4G and 4"", do not come into operation until thehygrostat 50 has reduced the amount of air admitted through dampers 53 and, relieved through dampers 5a to aminimum predetermined point. If the temperature then continues to fall, thermo stats46 and 47 function when it reaches 68 F, admitting a sufficient volume of steam to the heaters 42 and 43 to maintain this temperature of 68 F.

In general, he function of the various controls is to automatically vary the volume bf air admitted for ventilation in direct ra tio tothe number of people in the enclosure. In doing this, it also varies the amount of a 39 refrigeration required in like manner, be-

cause it varies the volume of fresh air admitted. and the dew point control and dein'the device 22, which under these condi ti'ons operates as a humidifier instead of as a dehumidifier.

' Comfortable air conditions can be thus automatically maintained for any'enclosure in which human beings assemble. The amount of refrigeration necessaryis reduced to aminimum, as'only' the comparatively small volume of fresh air fromtheoutside 5 passes through'the air conditionenor de A humidifier, "and the air ladened with sumsture from the. people is reliev'd into the at- ;mosphere without the necessity for condensation of this moisture in the dehumidifier.

full capacity of the dehumidifier 22 has been the summer months so that the annoyance and expense of operating a boiler during the summer is avoided and the heat of the people is utilized for the reheating of the" dehumidified cold air.

I claim as my invention:

1. The method of ventilating an enclosure in which people assemble, which includes withdrawing air from said enclosure, conditioning fresh air to provlde air having a I dew point lower than the dewpoint of the withdrawn air, mixing said conditioned fresh air with air withdrawn from the en closure and delivering the mixed air tothe enclosure, andvarying the proportions of said fresh air 1n the mixture in accordance with changes in the number of people in the enclosure.

2. The method of ventilating an enclosure in which people assemble, which includes withdrawing air from said enclosure, conditioning a volume of fresh air smaller than the volume of air withdrawn from the enclosure to provideair having a dew point lower than the dew point of the'wi-thdrawn air, mixing said conditioned air with air withdrawn from the enclosure and delivering the mixed air to the enclosure, and regula'ting'the volume of freshair which is conunder the control of the relative humidity in the enclosure i I p 3. The method of ventilating an enclosure in which people assemble, which includes humidifying fresh air to reduce its dew point below that. of the withdrawn air, mix

ing. said dehumidified air with air withdrawn from the enclosure and delivering the mixed airto the enclosure, and regulating the volume of fresh air which is dehumified and mixed with ,the withdrawn air in accordance with changes in the number of people in the enclosure. 4. The method of ventilating-an enclosure in which people assemble, which includes.

withdrawing-air from said enclosure, dehumidifying fresh air and maintaining a substantially constant dew point thereof below that of the-withdraivn air, mixing said dehumidified air with air withdrawn from the enclosure-and delivering the mixed air tolthe enclosure, and regulating the volume of fresh air wl 'cli is dehumidified and mixed with the with rawn air under the control of ditionedand mixed with the withdrawn air withdrawing air from said enclosure, de i 55 The coldair from the dehumidifier is perair so as to avoid cold streaks in the air, and

the relative humidity in the enclosure.

- fectly blended or mixed with the recirculated 5. The method of cooling and ventilating the resultant temperature of the air introducted-into the room isnot sufficiently low to ca'use discomfort to the people thercim Thus, comfortable air conditions in the enclosure are produced most economically and with a smaller initial investment than with other systems. The reheating of cold, rehumidified air is entirely eliminated during an enclosure in which people assemble which includes continuously withdrawing air from said enclosure for recirculation, permitting i a portion of said air to be relieved into the outside atmosphere, mixing the remainder of which corresponds substantially in volume with the relieved air and is dehumidified and said air with fresh air fromthe outsidef rekicooled before mixture. with said withdrawn.

I. e a air, and introducing the mixed air irto the room..

6. The methodof cooling and ventilating is not more than substantially 53 F. lower in temperature than. the temperature in said enclosure.

10. In an apparatus for ventilating an en- Closure, the combination of an air dehumidi- -I an enclosure in which people assemble, which tier having an inlet for outside fresh air, a

, includes continuously withdrawing airfrom 70 said enclosure for recirculation,permitting a; portion of said air to be relieved into the outside atmosphere, mixing the remainder of said air with fresh air which is admittedv from the outside and is dehumidificd and cooled before mixing with .thewithdrawn air, introducing the mixed air into the room, and regulatii'ig the amount of air relieved into the atmosphere and the amount of fresh air taken from the atmosphere under the control of the relative humidity in the enclofsure;

7. The method of ventilating an enclosure 1 in which people assemble, which includes withdrawing air from said enclosure, conditioning fresh air to provide air having a dew point lower than the dew point of the withdrawn air, mixing said conditioned fresh air with air withdrawn from the enclosure, and delivering theinixed air to the enclosure, varying the proportions of said fresh air in the mixture in' accordance with changes in the number of people in the enclosure, and regulating the temperature of the mixed air delivered into said enclosure under control of the temperature of the air withdrawn from said enclosure. I

8. The method of cooling and ventilating i an enclosure in which people assemble, which includes continuously withdrawing air from said enclosure for recirculation, permitting. a portion of said air to be relieved into the outside atmosphere, mixing the remainder of said air with fresh air which has been admitted from the outside and is dehumiditied and cooled before mixing with the withdrawn air, introducing the mixed air into the enclosure, controlling the minimuii temperature of the air introduced into-said enclosure under the control of the temperature of the air withdrawn-"from said" enclosure, and controlling the maximum temperature and relative humidity in theenclosure by 50. grostatically under control of the humidity of the air withdrawn from saiden'closure. .9. The method of cooling. and ventilating an enclosure in which people assemble, which includes withdrawing air, from. said enclo sure, recirculating and returning to the enclosure at least a portion of said withdrawn air, mixing fresh air from the outside with said withdrawn air after said fresh air has been cooled and dehumidified and delivering 69 the mixed air to the enclosure, and regulating the proportions of said returned air and dehumidificd air so that the temperature o mixed air introduced into said enclosure fier, and means for correspondingly varying vthe relief of air from said enclosure. 11. In an apparatus for ventilating an enclosure, the combination of an air dehumidi tier having an inlet for outside fresh air,

a mixing chamber connected with the outlet of said dehumidifier, a fan for drawing fresh air through said dehumidifier and mixing chamber, branch air passages connecting thedischarge of said fan to different portions of said enclosure, a second fan and'suc-tion connections for withdrawing ail from said diiferent portions of said enclosure, a return air passage connecting the discharge, of said second fan to. said mixing chamber, means for the relief of air from said enclosure to the outside atmosphere, means ,for-varying the admission of fresh air to said dehumidifier, and means for correspondingly varying the relief of air from Said enclosure.

12. In an apparatus for ventilating an enclosure, the combination of an air dehumidiiier having an inlet for outside fresh air, a mixing chamber connected with the outlet of said dehumidifier, a fan for draw ing fresh air through said dehumidifier and mixing chamber, branch air passages connecting the discharge of said fan to different portions of said enclosure, a second fan and suction connections for withdrawing air from said different portions of said encloi sure, a return air passage connectingthe discharge ofsaid second fan to said mixing chamber, means for the relief of a'ir"from said -enclos-ure to the outside atmosphere,

fresh air to the dehumidifier and correspondingly varying the relief of air from said en closure.

LEO L. LEWIS.

so i 

